Opal is one of the most beautiful — and most misunderstood — gemstones in the world. Because its colour can be imitated and "stretched" in clever ways, a lot of people genuinely aren't sure whether the opal they own (or are about to buy) is the real thing. As Adelaide opal specialists, it's one of the questions we're asked most. Here's how to tell.
First: "real" opal comes in a few honest forms
Before you worry about fakes, it helps to know there are three legitimate forms of genuine opal — all "real," but not the same thing, and not priced the same:
- Solid opal — a single, whole piece of natural opal. The most valuable and most durable.
- Doublet — a thin slice of genuine opal bonded to a dark backing to make the colour pop. Real opal, more affordable. See doublets →
- Triplet — a slice of genuine opal on a dark backing, with a clear protective dome on top. Real opal, hard-wearing, very affordable. See triplets →
None is "fake" — but a doublet or triplet should always be sold as a doublet or triplet, and priced accordingly. The problem is only when one is passed off as a solid stone.
How to spot a doublet or triplet
Look at the stone from the side, not just the top:
- A solid opal has colour and texture running right through it, with no perfectly straight join line.
- A doublet shows a flat, dead-straight line where the opal meets its dark backing.
- A triplet shows two lines — opal in the middle, dark backing below, glassy clear cap above. The very domed, glassy top is a giveaway.
If a stone is set in a closed-back setting the join can be hidden — which is exactly why you buy from someone who tells you plainly what it is.
Real opal vs man-made imitation
There are lab-made imitation opals (you may see the name "Gilson"). Genuine Australian opal almost always shows irregular, random patches of colour that shift as you tilt it. Many imitations show a too-perfect, repeating "snakeskin" pattern and an unnaturally even, plasticky look. Natural opal also tends to feel cool to the touch and has tiny natural inclusions.
Quick at-home checks (and their limits)
- The side view — the single most useful check.
- Play-of-colour — genuine opal's flashes shift as you move it; printed or imitation "colour" stays static.
- Pattern — natural opal is random and organic; too-regular = be suspicious.
We'd gently warn against water, scratch and heat tests from online — they can damage a doublet or triplet (water can seep into the join and cloud it) and won't tell you much. When in doubt, don't experiment on the stone.
The simplest answer: ask a specialist
A genuine opal dealer will tell you exactly what a stone is — solid, doublet or triplet, its type and origin — before you buy. If someone won't, that's your answer. We're always happy to look at an opal and tell you honestly what you have, no obligation.
Visit us at 14 King William Street, Adelaide, call (08) 8211 9995, or browse our genuine Australian opal jewellery online.